CN114485389A - Distortion aberration correction processing device, distortion aberration correction method, and storage medium - Google Patents
Distortion aberration correction processing device, distortion aberration correction method, and storage medium Download PDFInfo
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Abstract
The invention provides a distortion aberration correction processing device, which can correct distortion aberration with high precision even in the state that the optical axis of an image pickup device is inclined relative to the surface of a measured object. The storage unit stores distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates on an image plane and a distance from a reference point, for each of a plurality of segments on the image plane of the imaging device divided by a plurality of boundary lines radially extending from the reference point. The processing unit selects at least one section from the plurality of sections based on the coordinates of the correction target portion in the image plane, determines a coordinate correction rate based on the distortion correction information of the selected section and the distance from the reference point to the correction target portion, and corrects the coordinates of the correction target portion based on the determined coordinate correction rate.
Description
The present application claims priority based on japanese patent application No. 2020-178944, filed on 26/10/2020. The entire contents of this japanese application are incorporated by reference into this specification.
Technical Field
The present invention relates to a distortion aberration correction processing apparatus, a distortion aberration correction method, and a storage medium.
Background
In an ink jet apparatus that performs drawing by dropping ink from an ink jet head onto an object, a laser processing apparatus that performs drilling by making a laser beam incident on the object, a laser annealing apparatus that performs annealing by making a laser beam incident on a semiconductor substrate as an object, and the like, alignment marks provided on the object are detected to position the object. At this time, the position of the alignment mark is detected by performing image processing on the image in which the alignment mark is captured.
In order to detect the position of the alignment mark with high accuracy, it is preferable to correct distortion aberration of the lens (for example, patent document 1). In the distortion aberration correction method disclosed in patent document 1, a five-dimensional polynomial correction formula is set as a function of adjusting the distance (image height) from the origin of the image plane to the distorted image to the distance before distortion. The distance after distortion is corrected to the distance before distortion using the polynomial correction equation.
Patent document 1: japanese patent laid-open publication No. 2001-133223
When the optical axis of the imaging device is inclined with respect to the surface of the measurement object, the amount of distortion to be corrected varies depending on the position in the circumferential direction around the origin of the image plane. However, in the correction method disclosed in patent document 1, distortion is corrected only by the distance from the origin of the image plane, and therefore, distortion aberration cannot be corrected with high accuracy in a state where the optical axis of the imaging device is tilted.
Disclosure of Invention
The invention aims to provide a distortion aberration correction processing device, a distortion aberration correction method and a storage medium, wherein distortion aberration can be corrected with high precision even in a state that the optical axis of an imaging device is inclined relative to the surface of a measuring object.
According to an aspect of the present invention, there is provided a distortion aberration correction processing apparatus including:
a storage unit that stores distortion aberration correction information for each of a plurality of segments on an image plane of an imaging device, the segments being divided by a plurality of boundary lines radially extending from a reference point, the distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates on the image plane and a distance from the reference point; and
and a processing unit that selects at least one of the plurality of zones according to coordinates of a part to be corrected within the image plane, determines a coordinate correction rate according to the distortion aberration correction information of the selected zone and a distance from the reference point to the part to be corrected, and corrects the coordinates of the part to be corrected according to the determined coordinate correction rate.
According to another aspect of the present invention, there is provided a distortion aberration correction method including the steps of:
an imaging device is used for imaging a measurement object, wherein distortion aberration correction information of each of a plurality of sections within an image plane of the imaging device, the sections being divided by a plurality of boundary lines radially extending from a reference point, is known, the distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates within an image and a distance from the reference point,
a correction target portion to be subjected to coordinate correction in the image plane is determined,
selecting at least one section from the plurality of sections according to a position of the correction target site within the image plane,
determining a coordinate correction rate from the distortion aberration correction information of the selected segment and a distance from the reference point to the correction target portion,
correcting the coordinates of the correction target portion according to the determined coordinate correction rate.
According to still another aspect of the present invention, there is provided a storage medium storing a program executed by a computer to execute the steps of:
acquiring an image of a measurement object captured using an imaging device, wherein distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates within the image and a distance from a reference point is known for each of a plurality of segments within an image plane of the imaging device divided by a plurality of boundary lines radially extending from the reference point;
determining a correction target portion to be corrected from an image captured using the imaging device;
selecting at least one section from the plurality of sections according to coordinates of the correction target site in the image plane;
determining a coordinate correction rate from the distortion aberration correction information of the selected segment and a distance from the reference point to the correction target portion; and
correcting the coordinates of the correction target portion according to the determined coordinate correction rate.
By dividing the image plane into a plurality of segments and correcting distortion using distortion aberration correction information set for each segment, distortion aberration can be corrected with high accuracy even in a state where the optical axis of the imaging device is inclined with respect to the surface of the measurement object.
Drawings
Fig. 1 is a block diagram of a distortion aberration correction processing apparatus according to an embodiment.
Fig. 2 is a diagram showing the contents of distortion aberration correction information.
Fig. 3 is a diagram for explaining a method of correcting coordinates of a part to be corrected in an image plane.
Fig. 4 is a flowchart showing a procedure of correcting coordinates of a part to be corrected in an image plane.
Fig. 5 (a) is a diagram showing the distribution of images obtained by imaging a plurality of markers arranged in a matrix using a telecentric lens, and fig. 5 (B) is a diagram showing the coordinates of the markers after correction calculated from the coordinates of the images of the markers using the method of the present embodiment.
Fig. 6 (a) and (B) are views showing images of marks in an image plane when no distortion aberration is assumed and when distortion aberration is assumed in a case where the optical axis of the imaging device is perpendicular to the surface of the measurement object, respectively, and fig. 6 (C) is a graph in which a coordinate correction rate D in the x direction with respect to the diagonal direction of the image plane is plottedxAnd a distance r from the center point of the image plane.
Fig. 7 (a) and (B) are diagrams showing images of marks in an image plane when no distortion aberration is assumed and when distortion aberration is assumed in a case where an optical axis of an imaging device is inclined with respect to a surface of a measurement object, respectively, and fig. 7 (C) is a diagram in which a coordinate correction rate D in an x direction with respect to a diagonal direction of the image plane is plotted without distinguishing four diagonal directions of the image planexGraph of the relationship with the distance r from the center point of the image plane, and (D) in FIG. 7 is a regionThe coordinate correction factor D in the x direction with respect to the diagonal direction of the image plane is plotted by the sections Q1 to Q4xAnd a distance r from the center point of the image plane.
Fig. 8 (a) is a schematic front view of an inkjet drawing apparatus according to another embodiment, and fig. 8 (B) is a diagram showing a positional relationship of the movable table, the ink discharge unit, and the imaging apparatus in a plan view.
Fig. 9 is a flowchart showing a procedure of drawing with the inkjet drawing device.
In the figure: 10-distortion aberration correction processing means, 11-input/output interface section, 12-processing section, 13-storage section, 14-program, 15-distortion aberration correction information, 20-inkjet drawing means, 22-base, 23-support member, 24-moving mechanism, 24X-X direction moving mechanism, 24Y-Y direction moving mechanism, 25-movable table, 30-ink discharge unit, 32-nozzle, 40-image pickup means, 41-image pickup means image plane, 50-control means, 80-substrate, 81-alignment mark.
Detailed Description
A distortion aberration correction processing apparatus according to an embodiment will be described with reference to fig. 1 to 9.
Fig. 1 is a block diagram of a distortion aberration correction processing apparatus 10 according to an embodiment. The distortion aberration correction processing device 10 according to the present embodiment includes an input/output interface unit 11, a processing unit 12, and a storage unit 13. The processing unit 12 may be a computer, for example. The storage unit 13 stores a program 14 to be executed by a computer. The storage unit 13 also stores distortion aberration correction information 15. The contents of the distortion aberration correction information 15 will be described later with reference to fig. 2. As the storage unit 13, for example, an auxiliary memory such as a Hard Disk Drive (HDD) or a Solid State Disk (SSD) can be used.
The processing section 12 acquires image data from the imaging apparatus 40 via the input/output interface section 11. The processing unit 12 performs image analysis to detect the coordinates of the image of the alignment mark in the image. The coordinates of the image are affected by the distortion aberration of the lens and deviate from the actual coordinates indicating the position of the actual alignment mark. The processing unit 12 corrects the coordinates of the image using the distortion aberration correction information 15 stored in the storage unit 13, thereby reducing an error with the actual coordinates of the alignment mark. After that, the corrected coordinates are transmitted to the control device 50 via the input/output interface unit 11. The control device 50 performs various processes based on the corrected coordinates of the alignment marks. The processing unit 12 and the control device 50 may be realized by a common computer. At this time, the processing unit 12 can transmit the corrected coordinates of the alignment marks to the control device 50 without passing through the input/output interface unit 11.
Fig. 2 is a diagram showing the contents of the distortion aberration correction information 15. An xy orthogonal coordinate system with the reference point O as the origin is defined on the image plane 41 of the imaging device 40 (fig. 1). The object point in the field angle range of the imaging device 40 is transferred onto the image plane 41. The image plane 41 is, for example, a square or a rectangle, and the reference point O is the center of the square or the rectangle. The x-axis and the y-axis are defined parallel to one side of the image plane 41.
The image plane 41 is divided into a plurality of segments Q1 to Q4 by a plurality of boundary lines BL radially extending from the reference point O. In the present embodiment, a line segment connecting the reference point O and the midpoint of each side of the image plane 41 is employed as the boundary line BL. The four boundary lines BL correspond to the positive and negative x-axis portions and the positive and negative y-axis portions, and the sections Q1 to Q4 correspond to the 1 st quadrant to the 4 th quadrant of the xy coordinate system, respectively.
An image point P corresponding to an observation point under the influence of lens distortion1From an image point P when the lens is assumed to be free of aberrations0Is deviated from the position of (1). The distortion aberration correction information 15 is for correcting the image point P1To obtain an image point P without aberration0Contains the coordinate correction rate D in the x directionxAnd a coordinate correction rate D in the y directiony。
Next, a method of determining the distortion correction information 15 in the section Q1 will be described. An image of an observation target object on which a plurality of markers having known positions are formed is captured by an imaging device 40 (fig. 1) to acquire an image. The plurality of marks are, for example, lattice points in a lattice pattern. The observation target is moved until the mark serving as the reference point of the observation target coincides with the reference point O on the image plane 41. For example, the position of the image of the mark may be detected by analyzing the image of the mark captured, and the observation target may be moved based on the detection result so that the image of the mark serving as the reference point matches the reference point O on the image plane 41. This step may be repeated a plurality of times in order to improve the accuracy of making both of them uniform.
By analyzing the obtained image, a plurality of image points located on the diagonal line of the section Q1 having the reference point O as one end are extracted from the plurality of marked image points. Marking one of the extracted plurality of pixels as P1. Will be associated with the image point P1The corresponding aberration-free image point is marked as P0. Determining an image point P by image analysis1The coordinates of (c). Will be associated with the image point P1Corresponding image point P without aberration0Coordinate of (a) is marked as (x)0，y0) To image point P1Coordinate of (a) is marked as (x)1，y1). The coordinate correction rate D in the x direction is defined by the following equationxAnd a coordinate correction rate D in the y directiony。
[ numerical formula 1]
Coordinate correction rate D in x directionxFrom an image point P without aberration0To the actual image point P1The amount of displacement x in the x direction1-x0And the image point P from the reference point O to the time of no aberration0Length x in x direction of0The ratio of. Coordinate correction rate D in y directionyFrom an image point P in the absence of aberration0To the actual image point P1The amount of displacement y in the y direction1-y0From the reference point O to the image point P without aberration0Length y in the y direction of0The ratio of. Generally, distortion aberration of a lens is small at the center of an image plane and large at the periphery. Therefore, the coordinate correction rate Dx、DyDepending on the distance r from the reference point O.
From the reference point O to the actual image point P1The distance r to is taken as horizontalAxis and correction of the coordinate in the x-direction by a factor DxPlotting on a graph as vertical axis for a plurality of image points P on a diagonal1The measurement result of (1). An approximation curve that approximates the distribution of the plotted plurality of points is determined. Thus, as shown in fig. 2, for the section Q1, the coordinate correction rate D in the x directionxDefined as a function of the distance r. Similarly, the coordinate correction rate D in the y directionyAlso defined as a function of the distance r. Thus, distortion aberration correction information 15 is obtained for the section Q1. In the graph of the distortion aberration correction information 15 in the section Q1 shown in fig. 2, the coordinate correction rate D in the x direction is indicated by a thick solid line and a thin solid line, respectivelyxAnd a coordinate correction rate D in the y directionyAn example of the method.
The distortion correction information 15 can be obtained for the other segments Q2 to Q4 by the same method. The obtained distortion correction information 15 is stored in the storage unit 13 (fig. 1). Coordinate correction rate D in the case where distortion aberration does not depend on the radiation direction centered on the reference point Ox、DySubstantially the same between the sections Q1-Q4. However, in practice, the coordinate correction rate D is based on various reasonsx、DyThere is a deviation between the sections Q1-Q4. Examples of the cause of the deviation include inclination of the optical axis of the imaging device 40 with respect to the surface of the observation target.
Next, a method of correcting the coordinates of a certain portion (hereinafter, referred to as a correction target portion) in the image plane 41 to the coordinates when there is no aberration will be described with reference to fig. 3 and 4.
Fig. 3 is a graph for explaining a method of correcting the coordinates of the correction target portion Pt in the image plane 41. Fig. 4 is a flowchart showing a procedure of correcting the coordinates of the correction target portion Pt in the image plane 41.
First, a correction target portion Pt in the image plane 41 is specified. The calibration target portion Pt corresponds to, for example, the center point of the image of the alignment mark. Two zones are selected from the four zones Q1 to Q4 according to the position of the correction target site Pt (step S1). For example, two segments on both sides of the boundary line BL that makes the smallest angle with respect to the direction from the reference point O toward the correction target site Pt, out of the boundary lines BL that divide the four segments Q1 to Q4, are selected. In fig. 3, the positive portion of the y-axis corresponds to the boundary line BL satisfying this condition. Two sections Q1 and Q2 on either side of the positive portion of the y-axis are selected.
Next, the coordinate correction rate D of the segments Q1 and Q2 corresponding to the distance r from the reference point O to the correction target portion Pt is corrected based on the distortion aberration correction information 15 (fig. 1 and 2) of the selected two segments Q1 and Q2, respectivelyx、DyA coordinate correction rate D at the position of the part Pt to be corrected is obtained by performing a weighted averagext(r)、Dyt(r) (step S2). For example, the weighted average is performed based on the angle between the direction from the reference point O toward the geometric centers of the two selected sections Q1, Q2 (corresponding to the diagonal direction of the sections Q1, Q2) and the direction from the reference point O toward the correction target site Pt.
Angles formed by the directions from the reference point O to the geometric centers of the two selected segments Q1, Q2 and the directions from the reference point O to the correction target site Pt are denoted by θ1、θ2The coordinate correction rate D of the correction target part Ptxt(r)、Dyt(r) is represented by the following formula.
[ numerical formula 2]
Wherein D isx1(r)、Dy1(r) coordinate correction ratios in the x-direction and y-direction, D, respectively, obtained for the section Q1x2(r)、Dy2(r) are coordinate correction rates in the x direction and the y direction obtained for the segment Q2, respectively.
Then, the coordinate correction rate D is obtained from the weighted average of the coordinates on the correction target portion Ptxt、DytThe coordinates of the part Pt to be corrected in the image plane are corrected (step S3). For example, the coordinate of the correction target portion Pt is denoted by (x)1，y1) And the corrected coordinates are marked as (x)0，y0) Then, the corrected coordinates are calculated using the following equation.
[ numerical formula 3]
Next, the excellent effects of the present embodiment will be described with reference to (a) and (B) in fig. 5.
Fig. 5 (a) is a diagram showing the distribution of images obtained by imaging a plurality of markers arranged in a matrix using a telecentric lens. In fig. 5 (a), the amount of shift from the image of the mark in the case of no aberration to the actual image is enlarged by 100 times. As can be seen from fig. 5 (a), barrel-shaped distortion aberration occurs.
Fig. 5 (B) is a diagram showing the coordinates of the corrected image of the marker calculated from the coordinates of the actual image of the marker using the method of the present embodiment. Fig. 5 (B) also shows the amount of shift from the mark image without aberration to the coordinate-corrected image, enlarged by 100 times. As is clear from fig. 5 (B), distortion aberration is corrected, and a distribution close to the original matrix arrangement is obtained.
In this way, by using the method of the above embodiment, the distortion aberration of the lens can be corrected so that the coordinates of the image of the mark are close to the coordinates when there is no aberration.
Next, the reason why the distortion aberration can be corrected with high accuracy even in a state where the optical axis of the imaging device 40 (fig. 1) is inclined with respect to the surface of the measurement object will be described with reference to fig. 6 and 7.
Fig. 6 (a) and (B) are views showing the marks on the image plane 41 when no distortion is assumed and when distortion is assumed when the optical axis of the imaging device 40 is perpendicular to the surface of the measurement object, respectively. In fig. 6, (a) and (B) have horizontal and vertical axes indicating positions in the x and y directions, respectively. A plurality of marks are arranged on lattice points of the lattice pattern. In fig. 6, (a) and (B), the image of the mark is represented by a black-painted circular mark.
When no distortion aberration is assumed, the positions of the images of the plurality of marks coincide with the grid points of the square lattice as shown in fig. 6 (a). When the distortion aberration is assumed, the position of the image of the mark is deviated from the grid point as shown in fig. 6 (B). In fig. 6 (B), it is assumed that barrel-shaped distortion aberration significantly larger than that of a normal lens is generated.
In fig. 6, (C) is a coordinate correction rate D in the x direction in which the diagonal directions for the image plane are plotted without distinguishing the four diagonal directionsxAnd a distance r from the center point of the image plane. Since the distortion aberration has low dependency on the rotation direction with the center point of the image plane as the rotation center, a plurality of measurement points plotted for four diagonal directions can be accurately approximated with one approximation curve.
Fig. 7 (a) and (B) are views showing the images of the marks in the image plane 41 when no distortion aberration is assumed and when distortion aberration is assumed in the case where the optical axis of the imaging device 40 is inclined with respect to the surface of the measurement object, respectively. In fig. 7, (a) and (B) have horizontal and vertical axes indicating positions in the x and y directions, respectively. A plurality of marks are arranged on lattice points of the lattice pattern. In fig. 7, (a) and (B), the image of the mark is indicated by a black-painted circular mark.
Since the optical axis of the imaging device 40 is inclined, the position of the image of the mark is deviated from the grid point even if no distortion aberration is assumed, as shown in fig. 7 (a). Since there is no distortion aberration, the image of a straight line on the measurement object also becomes a straight line in the image plane. For example, when the outer peripheral line of the distribution region of the plurality of marks is square, the outer peripheral line of the distribution region of the image of the marks becomes trapezoidal in the image plane 41.
If the distribution of the image of the mark shown in fig. 7 (a) is assumed to generate the same aberration as the distortion aberration shown in fig. 6 (B), the distribution region of the image of the mark when the distortion aberration occurs is assumed to have a shape in which a trapezoid and a barrel are combined, as shown in fig. 7 (B).
In fig. 7, (C) is a graph plotting the coordinate correction rate D in the x direction with respect to the diagonal direction of the image plane 41 without distinguishing the four diagonal directions of the image plane 41xAnd a distance r from the center point of the image plane 41. Of aberration of distortionSince the size and orientation are different from each other in the diagonal direction, the plotted measurement points are distributed in a wider range in the vertical axis direction than the case shown in fig. 6 (C). Even if one approximation curve is set for the distribution, an error between the coordinate correction rate obtained from the approximation curve and the coordinate correction rate at each measurement point is large.
In fig. 7, (D) is a plot of coordinate correction ratios D in the x direction with respect to the diagonal direction of the image plane 41, with sections Q1 to Q4 being distinguishedxAnd a distance r from the center point of the image plane. The square marks, the triangular marks, and the circular marks in the graph plot the measurement points located on the diagonal lines of the sections Q2, Q3, and Q4, respectively. Although the coordinate correction rate is also calculated for a plurality of measurement points in the section Q1, the measurement points are not shown in fig. 7 (D).
The thin broken line, the thin solid line, the thick broken line, and the thick solid line in the graph of fig. 7 (D) are approximate curves that approximate the distribution of the measurement points of the coordinate correction rates in the x direction of the segments Q1 to Q4, respectively. When one segment is focused, the error between the coordinate correction rate obtained from the approximate curve and the coordinate correction rates at the plurality of measurement points is small.
When the optical axis of the imaging device 40 is inclined with respect to the surface of the measurement object, if the coordinates of the calibration target portion are corrected based on one approximate curve shown in fig. 7 (C), the error between the coordinates after correction and the coordinates when there is no aberration increases depending on the position of the calibration target portion. In contrast, in the present embodiment, in step S1 (fig. 4), two approximation curves that more accurately reflect the coordinate correction rate on the correction target portion among the four approximation curves shown in fig. 7 (D) are selected.
Then, in step S2 (fig. 4), the coordinate correction ratios obtained from the two approximation curves are weighted-averaged according to the degree of reflection of the coordinate correction ratio at the correction target portion. Therefore, even when the optical axis of the imaging device 40 is inclined with respect to the surface of the measurement target object, the coordinates can be corrected using a coordinate correction rate close to the actual coordinate correction rate on the correction target portion. Therefore, the accuracy of correction of the coordinates can be improved.
Next, a modified example of the above embodiment will be explained.
In the above embodiment, the image plane 41 (fig. 2) is divided into four sections Q1 to Q4, but the number of sections is not limited to four. The number of the segments may be two or more. For example, in the example shown in fig. 7 (D), the approximate curves of the section Q1 and the section Q4 are approximate to each other, and the approximate curves of the section Q2 and the section Q3 are approximate to each other. Therefore, even if the section Q1 and the section Q4 are grouped into one section and the section Q2 and the section Q3 are grouped into one section, high coordinate correction accuracy can be maintained to some extent.
Further, in the above-described embodiment, a plurality of image points P on each diagonal of the four sections Q1 to Q4 are targeted1(fig. 2) the coordinate correction rate is found, and an approximation curve is set according to the coordinate correction rate. A plurality of image points P serving as a basis for setting an approximation curve1Other points P in the segment may be considered, not limited to the diagonal1The coordinate correction rate of (3) to set an approximation curve.
For example, for a plurality of image points P in a region sandwiched between two radial directions from the reference point O toward one sector1The coordinate correction rate may be obtained. At this time, a plurality of image points P in the segment are strongly reflected for setting1Preferably, the two radial directions are set such that the region sandwiched between the two radial directions contains the geometric center of the segment.
In the above embodiment, when two segments are selected in step S1 (fig. 4), two segments on both sides of the boundary line BL having the smallest angle with respect to the direction from the reference point O toward the correction target site Pt are selected from among the four boundary lines BL. In addition, two sections whose coordinate correction rates on the correction target site Pt are approximated with high accuracy may be selected.
For example, in the example shown in fig. 7 (D), the approximate curve of the section Q1 and the approximate curve of the section Q4 exhibit the same tendency with respect to the change in the distance r. This means that the coordinate correction rate on the correction target site Pt when the correction target site Pt is located within the section Q1 or the section Q4 is approximated with high accuracy in the section Q1 and the section Q4. Therefore, when the correction target site Pt is located in the section Q1 or the section Q4, it is preferable to select the section Q1 and the section Q4 as two sections in step S1 (fig. 4). For the same reason, when the site Pt to be corrected is located in the section Q2 or the section Q3, it is preferable to select the section Q2 and the section Q3 as two sections in step S1 (fig. 4).
Also, in the above-described embodiment, two sections are selected in step S1 (fig. 4), but one section may be selected. E.g. at an angle theta1In the case where (fig. 3) is 0 ° or sufficiently small, only the section Q1 may be selected. According to the angle theta1May determine whether one or two sections are selected.
Next, an inkjet drawing device according to another embodiment is described with reference to fig. 8 and 9. The inkjet drawing apparatus according to the present embodiment is mounted with a distortion aberration correction apparatus according to the embodiment shown in fig. 1 to 4.
Fig. 8 (a) is a schematic front view of the inkjet drawing device 20. A movable table 25 is supported on the base 22 via a moving mechanism 24. An xyz rectangular coordinate system is defined in which the x-axis and the y-axis are oriented in the horizontal direction and the z-axis is oriented vertically downward. The controller 50 controls the moving mechanism 24 to move the movable table 25 in both the x-direction and the y-direction. As the moving mechanism 24, for example, an XY stage including an X-direction moving mechanism 24X and a Y-direction moving mechanism 24Y can be used.
A substrate 80 to be drawn is held on the upper surface of the movable table 25. The substrate 80 is fixed to the movable table 25 by, for example, a vacuum chuck. Above the movable table 25, the ink discharge unit 30 and the imaging device 40 are supported by, for example, a gate-shaped support member 23.
The imaging device 40 images the upper surface of the substrate 80. More specifically, the image pickup device 40 picks up an image of a region within the field angle range of the image pickup device 40 in the upper surface of the substrate 80. The image acquired by the imaging device 40 is input to the distortion aberration correction processing device 10.
The control device 50 receives the positional information of the substrate 80 from the distortion aberration correction processing device 10. The control device 50 controls the moving mechanism 24 and the ink discharge unit 30 based on the positional information, and causes the ink to be dropped onto a predetermined position on the surface of the substrate 80. Thereby, a film of ink having a predetermined shape is formed on the surface of the substrate 80.
Fig. 8 (B) is a diagram showing a positional relationship in a plan view of the movable table 25, the ink discharge unit 30, and the imaging device 40. A substrate 80 is held on the upper surface of the movable table 25. Above the substrate 80, the ink discharge unit 30 and the imaging device 40 are supported. A plurality of nozzles 32 are provided on a surface of the ink discharge unit 30 facing the substrate 80. The control device 50 controls the moving mechanism 24 to move the movable table 25 in the x direction and the y direction, and the control device 50 controls the discharge of the ink from each nozzle 32 of the ink discharge unit 30.
Alignment marks 81 are formed at four corners of the substrate 80, respectively. The control device 50 operates the moving mechanism 24 so that each alignment mark 81 is arranged within the field angle range of the imaging device 40, and the imaging device 40 can image the alignment mark 81.
Fig. 9 is a flowchart showing a procedure of drawing with the inkjet drawing device. First, the control device 50 operates the moving mechanism 24 to move one alignment mark 81 into the field angle range of the imaging device 40 (step S11). After that, the image pickup device 40 picks up the alignment mark 81 (step S12). The captured image data is input to the distortion aberration correction processing device 10. The distortion aberration correction processing apparatus 10 analyzes the image of the alignment mark 81 to detect the coordinates of the image of the alignment mark 81 in the image plane (step S13). The detection of the coordinates of the image of the alignment mark 81 may use a known algorithm (e.g., pattern matching, etc.).
The distortion aberration correction processing device 10 corrects the coordinates of the image of the alignment mark 81 by executing the steps based on the embodiment shown in fig. 4 (step S14). The processing of steps S11 to S14 is repeated until the coordinates are corrected for all the alignment marks 81 (step S15).
When the coordinates are corrected for all the alignment marks 81, the distortion aberration correction processing device 10 transmits the corrected coordinates of the image of the alignment mark 81 to the control device 50 (fig. 8 (a) and (B)) (step S16). Control device 50 executes the drawing process based on the corrected coordinates of the image of alignment mark 81 (step S17).
Next, the excellent effects of the present embodiment will be described.
Since the inkjet drawing device according to the present embodiment is equipped with the distortion aberration correction processing device 10 shown in fig. 1 to 4, the position of the alignment mark 81 can be measured with high accuracy. In particular, even when the optical axis of the imaging device 40 is inclined with respect to the surface of the substrate 80, the measurement accuracy of the position of the alignment mark 81 can be suppressed from being lowered.
Next, a modification of the embodiment shown in fig. 8 and 9 will be described. In the embodiment shown in fig. 8 and 9, the distortion aberration correction processing device 10 according to the embodiment shown in fig. 1 to 4 is mounted on the inkjet drawing device, but the distortion aberration correction processing device 10 according to the embodiment shown in fig. 1 to 4 may be mounted on another device. For example, the present invention may be mounted in a laser processing apparatus that performs drilling by irradiating a laser beam onto an object, a laser annealing apparatus that performs annealing by irradiating a semiconductor substrate as an object with a laser beam, or the like.
The above embodiments are examples, and it is needless to say that a part of the structures shown in different embodiments may be replaced or combined. The same operational effects based on the same structure in the plurality of embodiments are not mentioned one by one in each embodiment. Moreover, the present invention is not limited to only the above-described embodiments. For example, various alterations, modifications, combinations, and the like may be made, as will be apparent to those skilled in the art.
Claims (5)
1. A distortion aberration correction processing device is characterized by comprising:
a storage unit that stores distortion aberration correction information for each of a plurality of segments on an image plane of an imaging device, the segments being divided by a plurality of boundary lines radially extending from a reference point, the distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates on the image plane and a distance from the reference point; and
and a processing unit that selects at least one of the plurality of zones according to coordinates of a part to be corrected within the image plane, determines a coordinate correction rate according to the distortion aberration correction information of the selected zone and a distance from the reference point to the part to be corrected, and corrects the coordinates of the part to be corrected according to the determined coordinate correction rate.
2. The distortion aberration correction processing apparatus according to claim 1,
the shape of the image plane is a square or a rectangle,
the reference point is located at the center of the image plane,
the plurality of boundary lines are four line segments connecting the center of the image plane and the midpoints of the four sides.
3. The distortion aberration correction processing apparatus according to claim 1 or 2,
the processing unit corrects the coordinates of the correction target region,
selecting two segments on both sides of a boundary line having a smallest angle with respect to a direction from the reference point toward the correction target portion among the plurality of boundary lines,
the coordinate correction rates of the distortion aberration correction information of the selected two segments are weighted-averaged according to an angle formed by a direction from the reference point toward the geometric center of each of the selected two segments and a direction from the reference point toward the correction target portion, and the coordinates of the correction target portion are corrected according to the weighted-averaged coordinate correction rate.
4. A distortion aberration correction method is characterized by comprising the following steps:
an imaging device is used for imaging a measurement object, wherein distortion aberration correction information of each of a plurality of sections within an image plane of the imaging device, the sections being divided by a plurality of boundary lines radially extending from a reference point, is known, the distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates within an image and a distance from the reference point,
a correction target portion to be subjected to coordinate correction in the image plane is determined,
selecting at least one section from the plurality of sections according to a position of the correction target site within the image plane,
determining a coordinate correction rate from the distortion aberration correction information of the selected segment and a distance from the reference point to the correction target portion,
correcting the coordinates of the correction target portion according to the determined coordinate correction rate.
5. A storage medium storing a program, characterized in that,
the program is executed by a computer to perform the steps of:
acquiring an image of a measurement object captured using an imaging device, wherein distortion aberration correction information indicating a relationship between a coordinate correction rate for correcting coordinates within the image and a distance from a reference point is known for each of a plurality of segments within an image plane of the imaging device divided by a plurality of boundary lines radially extending from the reference point;
determining a correction target portion to be corrected from an image captured using the imaging device;
selecting at least one section from the plurality of sections according to coordinates of the correction target site in the image plane;
determining a coordinate correction rate from the distortion aberration correction information of the selected segment and a distance from the reference point to the correction target portion; and
correcting the coordinates of the correction target portion according to the determined coordinate correction rate.
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| JP2020-178944 | 2020-10-26 | ||
| JP2020178944A JP2022069967A (en) | 2020-10-26 | 2020-10-26 | Distortion aberration correction processing device, distortion aberration correction method, and program |
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| WO2023095635A1 (en) * | 2021-11-25 | 2023-06-01 | 住友重機械工業株式会社 | Distortion aberration rate calculation method, and position detecting device |
| JP2023159993A (en) | 2022-04-21 | 2023-11-02 | キヤノン株式会社 | Monitoring device, monitoring method, computer program, and storage media |
| CN115908201B (en) * | 2023-01-09 | 2023-11-28 | 武汉凡德智能科技有限公司 | Method and device for quickly correcting hot zone of image distortion |
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| TW202217231A (en) | 2022-05-01 |
| KR20220055410A (en) | 2022-05-03 |
| TWI786856B (en) | 2022-12-11 |
| JP2022069967A (en) | 2022-05-12 |
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